Study On The Preparation And Properties Of Halogen Free And Low Smoke Flame Retardant EPDM/PP Composites

Polypropylene/ethylene-propylene-diene copolymer (PP/EPDM) has good weather resistance, heat and ozone resistance, good electric performance and shock resistance, and also has advance of low cost, continuous production and simple processing, which have been widely used in many areas, including automible industry, electric casings, interior decoration, insulation, and so on. However, PP/EPDM blend is flammable, and the limiting oxygen index (LOI) is about17.5%, which restricts the range of its application. Therefore, it is important to study its flame retardation. Along with the enhancement of environmental consciousness, halogen free flame retardant had been taken more and more attention for its environmental friendly, high efficiency. Intumescent flame retardants (IFR) is one of important halogen free flame retardants. This paper adopts the different types of flame retardants formula. The effect of the ratio and amount of flame retardant, mixing temperature and mixing time on the thermal stability, flame retardancy, and mechanical proprerties of EPDM/PP composites were investigated. The main research contents as follow.Part one:An intumescent flame retardant (IFR) system composed of melamine pyrophosphate (MPP) and pentaerythritol (PER) was used for flame retarding ethylene-propylene-diene-modified elastomer (EPDM)/polypropylene (PP) blends. The influence of palygorskite clay content on LOI, CONE parameters, thermal stability and mechanical properties of the EPDM/PP composites were studied. Synergistic effect of MPP on flame retardant PER/EPDM/PP composites were investigated. While with a MPP/PER ratio of3:2and with30%total amount, LOI of the composites could reach more than28%. The material mechanics performance improved obviously by adding palygorskite clay. Thus, EPDM/PP composite with more comprehensive performance expand its application scope.Part two:An intumescent flame retardant system composed of a new biomass charring agent-the potato waste residue (PWR), a small amount of expandable graphite (EG) and ammonium polyphosphate (APP) was used for flame retarding ethylene-propylene-diene-modified elastomer (EPDM)/polypropylene (PP) blends. The synergistic effect between ammonium polyphosphate, expandable graphite and the potato waste residue on the thermal and flame retardancy of EPDM/PP composite were investigated by LOI,CONE, TGA, SEM and mechanical properties. Analysis of the changes of surface morphology of carbon residue combustion and flame retardant dispersed in the matrix of flame retardants add material or not. It is found that LOI of the EPDM/PP/APP/PWR composite is higher than that of the EPDM/PP/APP and EPDM/PP/PWR composite. In comparison with the EPDM/PP/APP/PWR composites, the LOI values of the EPDM/PP/APP/PWR/EG ternary composites at the same additive loading increase. Introducing of PWR and EG had an obvious effect on the structure of the intumescent charry layers.Part three:An intumescent flame retardant system composed of a new biomass charring agent-banana stalks (BS), a small amount of expandable graphite (EG) and ammonium polyphosphate (APP) was used for flame retarding ethylene-propylene-dien-modified elastomer (EPDM)/polypropylene (PP) blends. The synergistic effect between ammonium polyphosphate, expandable graphite and banana stalks on the thermal and flame retardancy of EPDM/PP composite material were investigated by UL-94test, LOI, CONE, TGA, and SEM,. Analysis of the changes of surface morphology of carbon residue combustion and flame retardant dispersed in the matrix of flame retardants add material or not. It is found that the LOI value of the EPDM/PP/APP/BS composite is higher than the values of the EPDM/PP/APP and EPDM/PP/BS composites. In comparison with the EPDM/PP/APP/BS composites, the LOI of the EPDM/PP/APP/BS/EG ternary composites at the same additive loading increase. Introducing of BS and EG had an obvious effect on the structure of the intumescent charry layers.